Notes given to President Trump to help him sell Teslas in front of the White House included prices and reminded him to use terms like ‘affordable.’

Mr. Musk is fundamentally a creature of Silicon Valley, a scene that initiated an entire revolution in power dressing. The young masters of that universe dressed down to show that they were members of a new elite — one that refused to dress like the grown-ups they were about to topple. It was the defeat of the suit by the T-shirt.

Elon Musk, wearing a suit and dark blue tie, just arrived to applause from people seated in the gallery who recognized him. He appears to be unaccompanied, checking his phone and watching the House floor banter with arms crossed.